Heat riser Block off plate
- Thread starter LandoNick
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It is not threaded. There’s a press fit bushing in there. On the far side, the non-spring end of the shaft, is a freeze plug that is still available from Toyota. I’ve tried replacing that twice and both times I had an exhaust leak there.
Like I said, when I get my spare manifold set machined I will have both holes threaded so I can install a tapered plug (as seen in some other folks’ posts above). I’ve looked into this for two years and that really seems like the most foolproof way.
I also tried a through bolt with big fender washers, and even put JB Weld under the fender washers while tightening it down. The heat baked off the JB Weld within a week and both sides leaked. I just don’t think there’s an easy way to seal up those holes without tapered & threaded plugs. Maybe welding then shut would work, but I’ve heard cast iron is difficult to weld onto - that’s about my expertise.
Like I said, when I get my spare manifold set machined I will have both holes threaded so I can install a tapered plug (as seen in some other folks’ posts above). I’ve looked into this for two years and that really seems like the most foolproof way.
I also tried a through bolt with big fender washers, and even put JB Weld under the fender washers while tightening it down. The heat baked off the JB Weld within a week and both sides leaked. I just don’t think there’s an easy way to seal up those holes without tapered & threaded plugs. Maybe welding then shut would work, but I’ve heard cast iron is difficult to weld onto - that’s about my expertise.
Or just dremel off the tack welds holding the flap to the shaft and leave the shaft in place. That leaks where the shaft passes through the press fit bushing on the spring side anyway though. Like, I bet that probably leaked from the factory. It’s a tight fit, but there’s enough space that the shaft can cleanly rotate inside the bushing, and that’s enough room for it to leak. A small leak, yes, but I’m pursuing perfection here.
No. Red loctite is only up to about 450* F. Exhaust manifold is WAAAAY above that.
Do it right while the assembly is off the engine or you're gonna have to do it again later.
Tapping the holes for threaded plugs seems like the most secure method, but requires tools. You could always take it to a machine shop and have them do it.
But the method posted with a couple nuts and bolts and plugs seems like a good DIY method. I'm not sure who posted that - maybe you could ask for their source for the plugs.
Oh, I misunderstood your post. If you're tapping for tapered plug you don't need the thread sealant, but if you have it, won't hurt to use. May help seal the threads even though a tapered plug is supposed to seal itself.
- Thread starter
- #49
Thread dealer can hang in that temp?
Its 'locking' quality will probably fail at those temps, but it still may function as a sealant. Tapered (NPT) plugs seal and lock because of the metal-to-metal compression of the threads, you'll be fine whatever you do if you install the plugs good 'n tite.
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Yes, you may need a drift to help persuade it. Plug on firewall side needs to come out first. Should be able to pull out too, from side with spring. Twist. Penetrant.
- Thread starter
- #53
When hammering the plug on the firewall side am I Hammering away from the center of the manifold or toward the center?
The plug has to be removed to tap on the shaft. Plug will have to come out opposite of the way it went in, meaning toward firewall. Best to try and remove the shaft by twist/pull on the exposed end with vise grips, etc. Use penetrant. Then pop the end plug from inside out.
You haven't posted any pictures so it's unknown what you're actually working with.
Silver-Star subscription is your friend.
You haven't posted any pictures so it's unknown what you're actually working with.
Silver-Star subscription is your friend.
- Thread starter
- #55
Ok that makes sense. I will doing this tomorrow. So I wanted to get the info before I dive in.
- Thread starter
- #56
Ok I got the manifold drilled out and tapped. the issue I have not is the plugs that I have in there (brass pipe thread) deep backing out and loosening? I tried NPT plugs same issue. with some High temp RTV and with out. Anybody have any ideas.
You've posted zero pix of what you're working with so it's hard to know what's going on. An NPT threaded plug will 'lock' due to the taper and friction of the threads, if installed properly.
Can you have someone (or yourself) tack-weld the plugs? That will keep them from backing out. That would be my first choice. Muffler shop would do it.
If no, then JB Weld makes some 'Extreme Heat' putty that's made for exhaust manifolds. You could put on the threads, or even the outside of the plugs - but honestly, It's the last thing I'd want to do, though it might work to lock the plugs.
Don't know what else to tell ya....
Can you have someone (or yourself) tack-weld the plugs? That will keep them from backing out. That would be my first choice. Muffler shop would do it.
If no, then JB Weld makes some 'Extreme Heat' putty that's made for exhaust manifolds. You could put on the threads, or even the outside of the plugs - but honestly, It's the last thing I'd want to do, though it might work to lock the plugs.
Don't know what else to tell ya....
- Thread starter
- #59
Yeah I have put that stuff on the threads of the plug. I would assume the same on the plug just sealing based on the taper. might ba a dumb question. can you weld brass to cast? or would I use the black steal plugs? I will shoot some pics
- Thread starter
- #60
Thanks for the response!
